Access disconnection systems with arterial and venous line conductive pathway

ABSTRACT

An extracorporeal blood system includes: an extracorporeal blood machine; an arterial line extending from the extracorporeal blood machine; a venous line extending from the extracorporeal blood machine; and an access disconnection circuit for detecting a disconnection of at least one of the arterial or venous lines from a patient, the access disconnection circuit including (i) a signal generation source having first and second signal generation source electrical lines each in electrical communication with blood traveling through one of the arterial or venous lines, (ii) a conductive pathway electrically communicating blood traveling through the arterial line with blood traveling through the venous line, and (iii) a signal processing unit positioned and arranged to process a signal generated by the source to detect the disconnection of the at least one of the arterial and venous lines.

PRIORITY CLAIM

This application claims priority to and the benefit as a continuation ofU.S. patent application Ser. No. 13/412,249, filed Mar. 5, 2012,entitled, “Access Disconnection Systems Using Conductive Contacts”,which is a continuation of U.S. patent application Ser. No. 12/727,993,filed Mar. 19, 2010, entitled, “Access Disconnection Systems UsingConductive Contacts”, which is a continuation of U.S. patent applicationSer. No. 11/331,609, filed Jan. 16, 2006, entitled, “AccessDisconnection System And Methods”, which is a continuation of U.S.patent application Ser. No. 10/120,684, filed Apr. 10, 2002, entitled,“Access Disconnection System And Methods”, the entire contents of eachof which are hereby incorporated by reference and relied upon.

BACKGROUND OF THE INVENTION

The present invention relates generally to patient access disconnectionsystems and methods for medical treatments. More specifically, thepresent invention relates to the detection of patient accessdisconnection, such as the detection of needle or catheter dislodgmentduring dialysis therapy.

A variety of different medical treatments relate to the delivery offluid to, through and/or from a patient, such as the delivery of bloodbetween a patient and an extracorporeal system connected to the patientvia a needle or needles inserted within the patient. For example,hemodialysis, hemofiltration and hemodiafiltration are all treatmentsthat remove waste, toxins and excess water directly from the patient'sblood. During these treatments, the patient is connected to anextracoporeal machine, and the patient's blood is pumped through themachine. Waste, toxins and excess water are removed from the patient'sblood, and the blood is infused back into the patient. Needles orsimilar access devices can be inserted into the patient's vascularaccess in order to transfer the patient's blood to and from theextracoporeal machine. Traditional hemodialysis, hemofiltration andhemodiafiltration treatments can last several hours and are generallyperformed in a treatment center about three to four times per week.

During any of these hemo treatments, dislodgment of an access device canoccur, such as dislodgment of a needle or access device inserted intothe patient's vascular access including an arterio-venous graft orfistula. If not detected immediately, this can produce a significantamount of blood loss to the patient. The risks associated with a needledislodgment or other suitable condition are considerable. In thisregard, important criteria for monitoring blood loss include, forexample, the sensitivity, specificity and response time with respect tothe detection of needle dislodgment. With increased levels ofsensitivity, specificity, and response time, the detection of needledislodgment can be enhanced, and blood loss due to dislodgment can beminimized.

Typically, patients undergoing medical treatment, such as hemodialysis,hemofiltration or hemodiafiltration, are visually monitored in order todetect needle dislodgment. However, the needle may not be in plain viewof the patient or medical staff (i.e., it may be covered by a blanket)such that it could delay detection and, thus, responsive actions to betaken in view of dislodgment, such as stopping the blood pump of theextracorporeal machine to minimize blood loss to the patient.

Moreover, in view of the increased quality of life, observed reductionsin both morbidity and mortality and lower costs than in-centertreatments, a renewed interest has arisen for self care and home hemotherapies. Such home hemo therapies (whether hemodialysis,hemofiltration or hemodiafiltration) allow for both nocturnal as well asdaily treatments. During these self care and home hemo sessions,especially during a nocturnal home hemo session, when the patient isasleep, dislodgment risks are more significant because nurses or otherattendants are not present to detect the dislodgment.

Although devices that employ a variety of different sensors areavailable and known for detecting and/or monitoring a variety ofdifferent bodily fluids, these devices may not be suitably adapted todetect needle dislodgment. For example, known devices that employsensors including pH, temperature and conductivity have been utilized todetect bedwetting and diaper wetness. Further, devices that employpressure sensors and/or flow sensing devices are known and used duringmedical treatment, such as dialysis therapy, to monitor fluid flowincluding blood flow to and/or from the patient. However, these types ofdetection devices may not provide an adequate level of sensitivity andresponsiveness if applied to detecting blood loss from the patient dueto needle dislodgment. Although venous pressure is known to be used tomonitor needle dislodgment, it is not very sensitive to needle-drop out.

Additional other devices and methods are generally known to monitorvascular access based on the electrical conductivity of blood. Forexample, Australian Patent No. 730,338 based on InternationalPublication No. WO 99/12588 discloses an electronic device that inducesa current in the extracorporeal blood circuit. The current is induced bya field coil placed around two points in the blood circuit therebydefining a closed conductor loop along the entire blood circuit. Thiscan be problematic from both a patient health and safety perspective andthe effective detection of needle-drop out or other vascular accessconditions.

In this regard, the blood circuit is coupled to a blood treatment systemthat includes a number of high impedance components, such a blood pump,air bubble traps, pinch clamps and/or the like. Because of the largeimpedance of the conducting fluid-loop (due to the peristaltic pump andother components), the induction and detection of a patient-safe currentrequires an impractically complex design of the coil and system.Further, a high level of noise would necessarily result from the use ofsuch levels of induced current. This can adversely impact thesensitivity of detection. If lower currents are used, the field coilwould have to be increased in size to detect such low current levels.This may not be practical in use, particularly as applied duringdialysis therapy.

PCT Publication No. WO 01/47581 discloses a method and device formonitoring access to the cardiovascular system of a patient. The accessmonitoring employs an electrical circuit which can generate and detect acurrent at separate points along a blood circuit connected to thepatient. Electrical current is injected into the fluid using capacitivecouplers that each have a metal tube placed around the blood circuittubing. In this regard, the metal tube defines a first plate of acapacitor; the blood circuit tubing defines the dielectric; and theblood inside of the blood circuit tubing defines the second plate of thecapacitor.

The generator applies a potential difference between a pair ofcapacitive couplers to generate a current in a segment of the bloodcircuit. A detector utilizes an additional and separate pair ofcapacitive couplers to measure the current along at least one section ofthe venous branch between a first contact point and the venous needle.The change in voltage (dV) can then be determined based on a measuredchange in current and compared to a reference range (I) to monitoraccess conditions. In this regard, PCT Publication No. WO 01/47581requires a complex circuit design that utilizes multiple sets ofcapacitive couplers to maintain vascular access. This can increase thecost and expense of using same.

Further, the measure of capacitive coupling to inject and electricsignal in the blood circuit and/or for detection purposes can beproblematic. In this regard, the signal must pass through the tubing ofthe blood circuit as the tubing acts as a dielectric of the capacitor.This may cause an excess level of noise and/or other interference withrespect to the detection of changes in vascular access conditions.

In this regard, it is believed that known devices, apparatuses and/ormethods that can be used to monitor a patient's vascular access may notbe capable of monitoring vascular access, particular the detection ofneedle-drop out during dialysis therapy, with sufficient sensitivity andspecificity to ensure immediate detection of blood loss such thatresponsive measures can be taken to minimize blood loss. As applied, iftwenty seconds or more of time elapses before blood loss due todislodgment of the venous needle, over 100 milliliters in blood loss canoccur at a blood flow rate of 400 ml/min, which is typical of dialysistherapy. Thus, the capability to respond quickly upon immediatedetection of needle dislodgment is essential to ensure patient safety.

Accordingly, efforts have been directed at designing apparatuses,devices, systems and methods for detecting changes in access conditions,such as in response to needle dislodgment, wherein detection issensitive, specific and immediate in response to such access changessuch that responsive measures can be suitably taken to minimize bloodloss from the patient due to same.

SUMMARY OF THE INVENTION

The present invention provides improved devices, apparatuses, systemsand methods for detecting access disconnection during medical therapy.In particular, the present invention can detect dislodgment ordisconnection of an access device, such as a needle, catheter or thelike, inserted in a patient through which fluid can flow during medicaltherapy, such as dialysis therapy.

In general, the present invention includes any suitable type ofelectrical circuit that can generate, measure and/or process anelectrical signal as it passes along a conductive path defined within afluid circuit, such as an extracorporeal blood circuit during medicaltherapy including dialysis therapy. The blood circuit can be coupled toa blood treatment system through one or more access devices insertedwithin the patient. The access device can include, for example, needles,catheters or the like. In this regard, blood can be circulated into,through and out of the patient along the blood circuit.

The present invention can include a number of electrical connectionsand/or contacts that are spaced apart along the blood circuit to monitorpatient access conditions. In particular, this can be used to detectaccess disconnection with high reliability. In this regard, the presentinvention can provide enhanced detection capabilities without requiringextensive modifications to the monitored therapy, such as to anextracorporeal blood circuit used during dialysis therapy. It isbelieved that the detection of access disconnection can also be achievedwith the use of lower levels of current in contrast to known systems.

In an embodiment, the present invention includes a conductive connectionor pathway along a fluid circuit, such as between an inflow fluid lineand an outflow fluid line of the fluid circuit connecting a patient to amedical therapy system. This can define at least a segment including,for example, a loop along the fluid circuit, such as a extracorporealblood circuit, that can remain closed until access disconnection. Theloop can be adapted such that an electric current or other signalpassing therein can bypass one or more components of a medical systemcoupled to the fluid circuit, such as dialysis system including adialysis machine, a blood pump, a drip chamber, other like componentsand combinations thereof. The vascular access of the patient can then bemonitored by measuring a change in an electrical value in response toaccess disconnection, such as dislodgment of a needle or catheter fromthe patient through which fluid can flow.

In an embodiment, the present invention can utilize at least threeelectrical contact points spaced apart and positioned along the bloodcircuit or other suitable fluid circuit to monitor access conditions.For example, an electrical signal, preferably a current, can be injectedthrough a conductive pathway directly connecting a first contact pointto a second contact point positioned along the blood circuit. As theelectric signal passes therein, a change in an electrical value can thenbe measured using a third contact point positioned separate and apartfrom the first and second contact points. Alternatively, an electricalsignal or the like can be injected into the fluid circuit through asingle contact point where changes in the electrical value in responseto dislodgment can then be measured using the direct connection betweenthe two remaining electrical contact locations.

The present invention also provides an inductive coupler device that canbe more easily and effectively utilized to attach an induction coil to afluid circuit for detection purposes. In an embodiment, the inductivecoupler includes movable members attached at an end region. A coilmember, such as an induction coil, is placed around at least one of themovable members. This enables the induction coupler to move about theend region thus allowing it to be readily placed around and secured to afluid conduit, such as a blood circuit. In this regard, the inductivecoupler can be arranged in an open and closed position such that it canbe readily secured to the fluid conduit. As used herein, the term“inductive coupler” or other like terms, such as “inductive couplingdevice” mean any suitable device which can be used to attach aninduction coil to a fluid conduit, such as a blood circuit.

In an embodiment, the movable coupling members are composed of amaterial that has a high magnetic permeability. In this regard, themagnetic permeability of the movable coupling members is in an amounteffective to converge or direct an electromagnetic field through theinduction coil. This can enhance the electromagnetic flux through theinduction coil such that an electromagnetic signal can be effectivelyinjected and likewise measured in the blood circuit.

An advantage of the present invention is to provide improvedapparatuses, devices, systems and/or methods for detecting accessdisconnection.

A further advantage of the present invention is to provide improvedapparatuses, systems and/or methods for monitoring connections to avascular access during dialysis therapy.

Another advantage of the present invention is to provide improvedapparatuses, devices, systems and/or methods for access disconnectionduring selfcare and home hemo treatments, such as dislodgment of aneedle, a catheter or the like.

Moreover, an advantage of the present invention is to provide improvedapparatuses, devices, systems and/or methods for monitoring accessdisconnection with enhanced accuracy, sensitivity and responsivenesswith respect to the detection of same.

Still further, an advantage of the present invention is to provide animproved device that can readily and effectively attach an inductioncoil to a fluid conduit used for detection purposes, such as detectionof access disconnection.

Additional features and advantages of the present invention aredescribed in, and will be apparent from, the following DetailedDescription of the Invention and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates an embodiment of the present invention showing aconductive connection that can be used to bypass one or more componentsof a blood treatment system coupled to a patient along a blood circuit.

FIG. 2A illustrates injection of an electrical signal into the bloodcircuit using a conductive connection pursuant to an embodiment of thepresent invention.

FIG. 2B illustrates measurement of a change in an electrical value inresponse to access disconnection using a conductive connection pursuantto an embodiment of the present invention.

FIG. 3A illustrates an inductive coupler of an embodiment of the presentinvention in an open configuration as it is placed around a fluidconduit.

FIG. 3B illustrates an inductive coupler of an embodiment of the presentinvention in a closed configuration secured to the fluid conduit.

FIG. 3C illustrates an exploded view of an electrical contact couplingdevice in an embodiment of the present invention.

FIG. 3D illustrates a side sectional view of the coupling device of FIG.3C in an embodiment of the present invention.

FIG. 3E illustrates another embodiment of the coupling device of thepresent invention.

FIG. 3F illustrates another embodiment of the coupling device of thepresent invention showing a threaded engagement between the componentsof same.

FIG. 3G illustrates a sectional view of FIG. 3F.

FIG. 4A illustrates a dialysis machine in an embodiment of the presentinvention.

FIG. 4B illustrates a dialysis machine in another embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to apparatuses, devices, systems, and/ormethods for detecting access disconnection, such as dislodgment of aneedle, catheter or other access device inserted in the vascular accessof a patient undergoing medical therapy, such as dialysis therapy. Ingeneral, the present invention includes a suitable electrical circuitthat provides any number and variety of suitable contact points spacedapart and coupled to a fluid circuit, such as a blood circuit. Thecontact points can be utilized to inject an electric signal into thefluid (e.g., blood) flowing through the fluid circuit thereby defining aconductor loop along at least a portion of the fluid circuit. A changein an electrical value in response to in response to changes in accessconditions, such as access disconnection including needle-drop out.

It should be appreciated that the present invention is not limited tothe detection of needle dislodgment but can be utilized to detect thedislodgment or disconnection of any suitable access device. As usedherein, the term “access disconnection” or other like terms means anysuitable condition or event which can cause a loss or leak of anelectrically conductive fluid flowing along a fluid circuit connected tothe patient provided that a change in the electrical continuity betweenelectrical contacts coupled to the fluid circuit can be detected. Itshould be appreciated that a change in the electrical continuity asmeasured by an electrical value, such as impedance, may be detected evenin the absence of dislodgment of an access device from the patient. Theterm “access device” as used herein or other like terms means a suitabledevice that can be inserted within a patient such that fluid, includingblood, can pass to, through and/or from the patient via the accessdevice. The access device can include a variety of different andsuitable shapes, sizes and material make-up. Examples of an accessdevice includes needles, catheters, cannulas or the like. The accessdevice can be composed of any suitable material including, for example,stainless steel, plastic or like biocompatible materials.

Although in the embodiment set forth below the apparatus and/or deviceis designed for use in a dialysis therapy, such as hemodialysis,hemofiltration or hemodiafiltration, it should be noted that the presentinvention can be used in a number of different medical therapies thatemploy a variety of different and suitable fluid systems, such asextracorporeal blood systems. For example, the invention of the presentapplication can be used during intravenous infusion that can employ theuse of a single needle insertable within the patient for delivering amedical solution or drug, blood, blood products, processed blood or thelike between the patient and the fluid system. In addition, the presentinvention can be used in plasma exchange therapies, where a membrane isused to separate whole blood into plasma and cellular components.

With respect to dialysis therapy, the present invention can be used in avariety of different therapies to treat kidney failure. Dialysis therapyas the term or like terms are used throughout the text is meant toinclude and encompass any and all forms of therapies that utilize thepatient's blood to remove waste, toxins and excess water from thepatient. Such therapies include both intermittent, includinghemodialysis, hemofiltration and hemodiafiltration, and continuoustherapies used for continuous renal replacement therapy (CRRT). Thesecontinuous therapies include slow continuous ultrafiltration (SCUF),continuous veno venous hemofiltration (CVVH), continuous veno venoushemodialysis (CVVHD), and continuous veno venous hemodiafiltration(CVVHDF). Dialysis therapy can also include peritoneal dialysis, such acontinuous ambulatory peritoneal dialysis, automated peritoneal dialysisand continuous flow peritoneal dialysis. Further, although the presentinvention, in an embodiment, can be utilized in methods providing adialysis therapy for patients having chronic kidney failure or disease,it should be appreciated that the present invention can be used foracute dialysis needs, for example, in an emergency room setting. Lastly,as one of skill in the art appreciates, the intermittent forms oftherapy (i.e., hemofiltration, hemodialysis and hemodiafiltration) maybe used in the in center, self/limited care as well as the homesettings.

Access Disconnection

As illustrated in FIGS. 1, 2A and 2B, the present invention, in anembodiment, can be adapted to monitor access conditions during dialysistherapy. A patient is connected to a dialysis system 10 via anextracorporeal blood circuit 12 that includes an arterial blood line 14and a venous blood line 16 coupled to a vascular access 18 of thepatient via an arterial needle 20 and a venous needle 22 or othersuitable access device as shown in FIG. 1. In this regard, blood cancirculate into, through and out of the patient along the blood circuit12 during dialysis therapy.

The dialysis system 10 can include any number and variety of components.For example, the dialysis system includes any suitable clamp 24 or otherflow regulator, an air bubble trap or the like 26, a blood treatmentdevice 28, such as a dialyzer and a blood pump 29, such as a peristalticpump. The components can be coupled to the blood circuit asschematically shown in FIG. 1. Any one or combination of thesecomponents can be apart of a dialysis machine coupled to the bloodcircuit, as described below. During treatment, blood passes from thepatient through the arterial blood line 14, into the blood treatmentdevice 28 and circulates back into the patient along the venous bloodline 16.

As previously discussed, the present invention can include any suitabletype of electrical circuit and design to effectively detect accessdisconnection during medical therapy. In an embodiment, the presentinvention includes a pair of induction coils attached to the bloodcircuit 12 at separate locations. As shown in FIG. 1, a first inductioncoil 30 is attached to the venous blood line 16 and a second inductioncoil 32 is attached to the arterial blood line 14.

It should be appreciated that any suitable type of induction coil can beutilized, such as a field coil coupled to and around the blood circuit.The induction coil can be attached to the fluid circuit in any suitableway. For example, the field coil can be wound around the fluid circuit.In an embodiment, the induction coil is placed around at least onemember of a movable coupling device. The coupling device can be openedand closed allowing the induction coil to be readily and effectivelyplaced around the fluid circuit as described below.

In an embodiment, any suitable electric signal can be injected into theblood circuit. A level of current is generated with any suitable device34 and injected into the blood circuit at the first induction coil 30attached to the venous blood line 16. As the electric current passesthrough the blood circuit 12, the second coil 32 can measure a change inan electrical value due to changes in access conditions during dialysistherapy. A change in amperage, impedance or the like can be detectedwith high reliability in response to dislodgment of one or both of thevenous needle 22 and arterial needle 20 from the patient or other likedevices. Alternatively, the electric current can be induced into thevenous blood line and measured along the arterial blood line. As usedherein, the term “electrical value” or other like terms means anysuitable electrical parameter typically associated with electricalcircuitry including, for example, impedance, resistance, voltage,current, rates of change thereof and combinations thereof.

The induction coil 32 can be used to pass a signal based on themeasurable change in amperage or the like due to changes in accessconditions, such as needle or drop-out. The signal can then be detectedand further processed by a signal processing unit 33 connected to theinduction coil 32. The signal processing unit 33 can then be coupled toany suitable component of the blood treatment system, such as the bloodpump 29 and the clamp 24. In this regard, the blood pump 29 can beautomatically shut off and/or the clamp 24 can be automatically closedto controllably minimize blood loss to the patient in response to, forexample, needle-drop out or other suitable access disconnectionconditions.

Conductive Bypass

As shown in FIG. 1, the present invention includes a conductiveconnection 35 made between two contact points 36 positioned along thearterial blood line 14 and venous blood line 16. This forms a conductivepathway 38 thereby defining a conductor loop 40 that remains closeduntil access disconnection. This allows the electric signal passingtherein to bypass one or more of the components of the dialysis systemalong the blood circuit. In an embodiment, the conductive connection 35can be positioned allowing the conductive pathway to bypass all of thecomponents of the dialysis system 10 as shown in FIG. 1.

The bypass effectively acts to reduce the high impedance effects ofvarious components of the dialysis system, such as the air bubble trap26, the blood treatment device 28, the blood pump 29, the like andcombinations thereof. In this regard, the injection of a high level ofcurrent or the like into the blood circuit is not required to overcomethe high impedance effects of such components. This can facilitate thereliable detection of a change in impedance or other suitable electricalvalue in response to needle dislodgment. The use of high levels ofcurrent can necessarily result in a high level of noise which may impactdetection sensitivity. Further, the ability to inject a lower level ofan electrical signal, preferably current, in the blood circuit canbetter ensure the health and safety of the patient.

The conductive connection 35 can be formed in any suitable way. In anembodiment, the conductive connection 35 includes the conductive path 38in fluid contact with blood flowing through the arterial blood line 14and venous blood line 16 at the two contact points 36. The conductivepath 38 can be composed of any suitable conductive material, such as awire or other like conductive material such that the conductive path 38has an impedance that is less than the impedance of the component orcomponents of the dialysis system 10 that are bypassed. The impedance ofthe conductive path 38 is less than the impedance of the components inan amount effective to cause the electric current to bypass thecomponents, and thus follow the path of least resistance. Alternatively,the conductive connection 35 can be coupled to the venous and arterialblood lines with capacitive couplers and thus does not make fluidcontact with the blood.

Conductive Connection

As illustrated in FIGS. 2A and 2B, the present invention can includethree contact points positioned along the blood circuit 12. In anembodiment, the first contact point 42 includes an induction coilcapable of inducing an electric current or the like into the bloodcircuit. It should be appreciated that the electrical current or othersuitable signal can be injected into the blood circuit in any suitableway including using an induction coil (as previously discussed), acapacitive coupler, an electrical contact in fluid communication withthe blood and the like. The first contact point 42 is located on thevenous blood line 16 at a position before the components of the dialysissystem (refer to FIG. 1) along the blood circuit 12. The second contactpoint 44 is located on the arterial blood line 14 at a position beforethe components of the dialysis system along the blood circuit 12.Alternatively, the first 42 and second 44 contacts can be located on thearterial blood line 14 and the venous blood line 16, respectively.

The third contact point 46 can be located at any suitable positionbetween the first 42 and second contact 44 points along a portion of theblood circuit 12 that connects the first 42 and second 44 contact pointsto the components of the dialysis system as shown in FIGS. 2A and 2B.The second 44 and third 46 contact points form a direct conductiveconnection in the blood circuit 12. The direct connection between thesecond 44 and third 46 contact points can be made in any suitable way.For example, the second contact 44 and the third contact 46 can beattached to the blood circuit 12 via an induction coil, an electricalcontact in fluid contact with the blood, an electrical contactcapacitively coupled to the blood circuit and/or the like as the fluidflows along the blood circuit 12. Any suitable device can be used tomake an electrical connection with the fluid circuit, illustrativeexamples of which are described in detail below.

In an embodiment, the electric signal is injected into the blood circuitthrough the first contact point 42 in any suitable way, such as throughan induction coil, thereby defining a conductor loop along the bloodcircuit. The conductive connection made directly between the second 44and third 46 contact points can be utilized to measure a change in anelectrical value in response to access disconnection as shown in FIG.2A. Alternatively, the electrical signal can be generated and injectedthrough the direct conductive connection where the first contact point42 is used to measure a detectable change in the electrical value, suchas impedance or the like as shown in FIG. 2B.

The use of the direct connection between the second 44 and third 46contact points can facilitate the reliable detection of accessdisconnection, such as needle or catheter dislodgment. In this regard, alower level of current or the like can be used to for detectionpurposes. From a practical standpoint, it is believed that the use ofthe direct connection can be achieved without requiring extensivemodifications to the blood circuit as previously discussed.

The present invention provides a variety of different ways in which anelectrical contact can be attached to a fluid circuit, such as a bloodcircuit, for use during detection of access detection. By way of exampleand not limitation, illustrative examples are described below.

Induction Coil Coupling Device

In an embodiment, the present invention includes an induction coilcoupling device that can be more easily and effectively utilized tomonitor vascular access during therapy. In an embodiment, the couplingdevice 50 of the present invention includes a first member 52 that ismovably attached to a second member 54 at a first end 55 allowingdisplacement of the first member 52 and the second member 54 relative toone another. The first member 52 and the second member 54 can be movableattached in any suitable manner. For example, a hinge 56 or any othersuitable movable device can be used. A coiled member 57, preferably aninduction coil 57, is wrapped around at least a portion of the couplingdevice. In an embodiment, the induction coil is wrapped around a portionof the first movable member 52 as shown in FIGS. 3A and 3B.Alternatively the induction coil 57 can be wrapped around the secondmovable member 54, both members and portions thereof.

In FIG. 3A, the induction coupling device 50 of the present invention isin an open configuration such that it can be readily placed around afluid conduit (not shown), such as a blood line of a blood circuit.Next, the first member 52 and/or the second member 54 can be displacedto close and secure the coupling device 50 to the blood line as shown inFIG. 3B. In an embodiment, the first member 52 and the second member 54can be displaced to matingly engage in any suitable way at a second end.This enables the induction coupling device 50 to be easily attached to ablood circuit as compared to the mere use of an induction field coilwhich must necessarily be wound around the blood line of the bloodcircuit a multiple number of times for effective use.

In an embodiment, the movable members are composed of a material thathas a high magnetic permeability, such as a ferrite bead. In the closedposition, the movable members must meet in mating engagement. In thisregard, the movable members can effect act to converge or direct anelectromagnetic field through the induction coil 57. This can enhancethe electromagnetic flux through the induction coil allowing theinduction coupling device to be effectively used to detect accessdisconnection as previously discussed.

Electrical and Fluid Contact

In an embodiment, the present invention can include an electricalcontact coupling device that can be utilized to secure the electricalcontacts, preferably electrodes, to the blood circuit such that theelectrodes effectively contact the blood and, thus, can be used toeffectively monitor changes in access conditions as previouslydiscussed. The coupling device of the present invention can also bedesigned to facilitate the protection of the user against contact withpotential electrical sources. In an embodiment, the device can include aconductive element connected to a tube through which a medical fluid canflow wherein the conductive element has a first portion exposed to themedical fluid, such as blood, and a second portion external to the tube.

It should be appreciated that the coupling device of the presentinvention can include a variety of different and suitableconfigurations, components, material make-up or the like. In anembodiment, the present invention can include a device for connecting anelectrical contact to a fluid conduit providing fluid and electricalcommunication between the electrical contact and fluid flowing throughthe fluid conduit. The device can include a first member including anannular portion capable of accommodating the electrical contact and afirst stem portion connected to the annular member wherein the stemportion has an opening extending therethrough to the annular portion; asecond member including a base portion with a groove region and a secondstem portion with an opening extending therethrough to the groove regionallowing the first member to be inserted and secured to the secondmember; and a contact member adapted to fit the first and second stemportions allowing the contact member to abut against at least a portionof the electrical contact member allowing an electrical connection to bemade between the electrical contact and the contact member.

As illustrated in FIGS. 3C and 3D, the electrical contact couplingdevice 80 includes a probe member 82 that has a cylindrical shape withan opening 84 extending therethrough. In this regard, an electricalcontact, preferably an electrode 86 having a cylindrical shape can beinserted into the opening 84 such that the electrode 86 is secure withinthe probe member 82. In an embodiment, the probe member 82 has a channel85 extending along at least a portion of the opening 84 within which theelectrode 86 can be inserted into the probe member 82. A tube member,for example, from a blood tubing set, connector tube member of adialysis machine or the like, can be inserted into both ends of theopening 84 of the probe member 82 in contact with an outer portion ofthe channel 85 allowing blood or other suitable fluid to make fluidcontact with the electrode 86 in any suitable manner. The electrode 86has an opening 88 that extends therethrough within which blood (notshown) or other suitable fluid from the fluid circuit can flow. In anembodiment, the diameter of the opening 88 of the electrode 86 is sizedto allow blood flow through the electrode 86 such that blood flow levelsunder typical operating conditions, such as during dialysis therapy, canbe suitably maintained. In this regard, the coupling device of thepresent invention can be readily and effectively attached to a fluidcircuit, including a blood circuit or the like, for use during medicaltherapy including, for example, dialysis therapy. It should beappreciated that the coupling device 80 of the present invention can beattached to the fluid circuit in any suitable way such that electricaland fluid connection can be made with the fluid flowing through thefluid circuit.

The probe member 82 also includes a stem portion 90 that extends from asurface 92 of its cylindrical-shaped body. The stem portion 90 has anopening 93 that extends therethrough. In an embodiment, the stem portion90 is positioned such that at least a portion of the electrode 86 is incontact with the opening 93 of the stem portion 90.

In order to secure the electrode 86 to the blood circuit, the couplingdevice 80 includes a socket member 94 that includes a body portion 96with an opening 98 for accepting the probe member 82 and for accepting ablood tube member (not shown) of the blood circuit such that blooddirectly contacts the electrode as it circulates through the bloodcircuit during dialysis therapy. In an embodiment, the socket member 94includes a stem portion 100 extending from the body member 96 whereinthe stem portion 100 includes an opening 102 extending therethrough. Asthe probe member 82 is inserted through the opening 98 of the bodymember 96, the stem portion 90 of the probe member 82 can be insertedinto the opening 102 of the stem portion 100 of the body 96 of thesocket member 94.

In an embodiment, the socket member 94 includes a groove region 104extending along at least a portion of the body 96 of the socket member94. In this regard, the probe member 82 can be inserted through theopening 98 and then moved or positioned into the groove region 104 tosecure the probe member 82 within the body 96 of the socket member 94.

In an embodiment, the coupling device 80 includes an electrical contactmember 106 that is inserted within the opening 102 of the stem portion100 of the body 96 of the socket member 94 such that the electricalcontact member 106 extends through the opening 93 of the stem portion 90of the probe member 82 to contact at least a portion of a surface 108 ofthe electrode 86.

The electrical contact member 106 is utilized to connect the electronics(not shown) of, for example, the excitation source, a signal processingdevice, other like electronic devices suitable for use in monitoringand/or controlling changes in access conditions, such as needledislodgment. The electrical contact member 106 can be made of anysuitable material, such as any suitable conductive material including,stainless steel, other like conductive materials or combinationsthereof. In order to secure the electrical contact member 106 in place,a contact retainer member 110 is inserted within the opening 102 of thestem portion 100 at an end region 112 thereof.

In an embodiment, the coupling device can be mounted to a dialysismachine, device or system in any suitable manner. For example, thecoupling device can be mounted as an integral component of the dialysismachine. As well, the coupling device can be mounted as a separateand/or stand alone component which can interface with any of thecomponents of the apparatus and system of the present invention. In anembodiment, the coupling device 80 can be insertably mounted via thestem portion 100 of the socket member 94 to a dialysis machine or othersuitable components.

It should be appreciated that the electrical contact coupling device caninclude a variety of different and suitable shapes, sizes and materialcomponents. For example, another embodiment of the coupling device isillustrated in FIG. 3E. The coupling device 114 in FIG. 3E is similar inconstruction to the coupling device as shown in FIGS. 3C and 3D. In thisregard, the coupling device 114 of FIG. 3E can include, for example, acylindrical-shaped electrode or other suitable electrical contact, aprobe member for accepting the electrode and securing it in place withina socket member of the sensing device. The probe member includes a stemportion that is insertable within a stem portion of the socket member.An electrical contact member is insertable within the stem portion suchthat it can contact the electrode. The coupling device of FIG. 3E canalso include a contact retainer member to hold the electrical contactmember in place similar to the coupling device as shown in FIGS. 3C and3D.

As shown in FIG. 3E, the probe member 116 of the electrical contactcoupling device 114 includes a handle 118 which can facilitate securingthe probe member 116 within the socket member 120. The handle 118, asshown, has a solid shape which can facilitate the use and manufacture ofthe coupling device 114. In addition, the stem portion (not shown) ofthe probe member 116 is larger in diameter than the stem portion of theprobe member as illustrated in FIG. 3C. By increasing the stem size, theprobe member can be more easily and readily inserted within the socketmember. Further, the probe member is greater in length as compared tothe probe member as shown in FIGS. 3C and 3D such that the end regions122 of the probe member 116 extend beyond a groove region 124 of thesocket member 120. This can facilitate securing the probe member withinthe groove region 124 of the socket member 120.

In an embodiment, an opening 126 of the socket member 120 can include anadditional opening portion 128 to accommodate the insertion of the stemportion of the probe member 116, having an increased size, therethrough.This can ensure proper alignment of the probe member with respect to thesocket member before insertion of the probe member into the socketmember thus facilitating the insertion process.

It should be appreciated that the probe member, socket member andcontact retainer member can be composed of a variety of different andsuitable materials including, for example, plastics, molded plastics,like materials or combinations thereof. The various components of thecoupling device, such as the probe member, socket member and contactretainer member, can be fitted in any suitable way. For example, thecomponents can be fitted in smooth engagement (as shown in FIGS. 3C and3D), in threaded engagement (as shown in FIGS. 3F and 3G) and/or anysuitable fitting engagement or arrangement relative to one another.

As shown in FIGS. 3F and 3G, the coupling device 130 of the presentinvention can be made of threaded parts which are removably andinsertably connected to one another to form the coupling device. Thethreaded parts can facilitate securing the electrode to the bloodcircuit as well as general use of same as described below.

In an embodiment, the stem portion 132 of the body 134 of the couplingdevice 130 has a threaded region 136 which can be insertably attached toa dialysis machine or other suitable mounting device in threadedengagement. This can facilitate the ease in which the coupling device isattached and detached from the mounting device.

As shown in FIG. 3G, the stem portion 132 is threaded on both sidesallowing it to be in threaded engagement with an annular member 138. Theannular member 138 provides direction and support allowing theelectrical contact member 140 to abut against the electrode 142 housedin the probe member 144 as previously discussed.

In an embodiment, a plate member 146 made of any suitable conductivematerial can be depressed against a spring 148 as the probe member 144is secured to the body 134. At the same time, another spring 150 can bedisplaced against the electrical contact member 140 in contact with theretainer 152 which is inserted within an annular region of the annularmember 138 to secure the electrical contact member 140 to the body 134.

The spring mechanism in an embodiment of the present invention allowsthe parts of the coupling device 130 to remain in secure engagementduring use. It can also facilitate use during detachment of the partsfor cleaning, maintenance or other suitable purpose.

As previously discussed, the present invention can be effectivelyutilized to detect dislodgment of an access device, such as a needle orcatheter, inserted within a patient through which fluid can pass betweenthe patient and a fluid delivery and/or treatment system. The presentinvention can be applied in a number of different applications, such asmedical therapies or treatments, particularly dialysis therapies. Indialysis therapies, access devices, such as needles or catheters, can beinserted into a patient's arteries and veins to connect blood flow toand from the dialysis machine.

Under these circumstances, if the access device becomes dislodged orseparated from the blood circuit, particularly the venous needle, theamount of blood loss from the patient can be significant and immediate.In this regard, the present invention can be utilized to controllablyand effectively minimize blood loss from a patient due to dislodgment ofthe access device, such as during dialysis therapy includinghemodialysis, hemofiltration, hemodiafiltration and continuous renalreplacement.

Dialysis Machine

As previously discussed, the present invention can be adapted for usewith any suitable fluid delivery system, treatment system or the like.In an embodiment, the present invention is adapted for use with adialysis machine to detect access disconnection as blood flows betweenthe patient and the dialysis machine along a blood circuit duringtreatment, including, for example hemodialysis, hemofiltration andhemodiafiltration.

The present invention can include any suitable dialysis machine for suchpurposes. An example, of a hemodialysis machine of the present inventionis disclosed in U.S. Pat. No. 6,143,181 herein incorporated byreference. In an embodiment, the dialysis machine 190 comprises a mobilechassis 192 and it has at the front side 194 thereof a common mechanism196 for connecting tubing or the like by which a patient can beconnected to the dialysis machine as shown in FIG. 4B. A flat touchscreen 197 which can show several operational parameters and is providedwith symbols and fields for adjustment of the dialysis machine byrelevant symbols and fields, respectively, on the screen being touchedcan be adjusted vertically and can be universally pivoted on thedialysis machine and can be fixed in the desired adjusted position.

In an embodiment, the dialysis machine includes a chassis having one ormore connectors for connecting a patient to the dialysis machine via ablood circuit allowing blood to flow between the patient and thedialysis machine during dialysis therapy wherein one or more electricalcontacts are connected to the blood circuit in fluid communication withthe blood allowing detection of a change in an electrical value inresponse to access disconnection as the blood flows through the bloodcircuit having an electrical signal passing therein as previouslydiscussed.

In an embodiment, the dialysis machine of the present invention can bedesigned to accommodate one or more of the coupling devices, such as aninduction coil coupling device and other such coupling devices aspreviously discussed, used to detect access disconnection as shown inFIG. 4B. For example, one or more coupling devices 198 can be attachedto the front panel 194 of the dialysis machine 190. This can be done inany suitable way. In an embodiment, a stem portion of the couplingdevice is insertably mounted via a threaded fit, frictional fit or thelike, as previously discussed. This connects the patient to the dialysismachine 190 via a blood tubing set 202. The blood tubing set includes afirst blood line 204 and a second blood line 206. In an embodiment, thefirst blood line 204 is connected to the patient via an arterial needle208 or the like through which blood can flow from the patient 200 to thedialysis machine 190. The second blood line 206 is then connected to thepatient 200 via a venous needle 210 or the like through which fluidflows from the dialysis machine to the patient thereby defining a bloodcircuit. Alternatively, the first blood line and the second blood linecan be coupled to the venous needle and the arterial needle,respectively. The blood lines are made from any suitable medical gradematerial. In this regard, access disconnection, such as dislodgment ofan arterial needle and/or a venous needle can be detected as previouslydiscussed. Alternatively, the coupling device can be attached to theblood tubing set which is then attached to the dialysis machine in anysuitable way.

Dialysis Treatment Centers

As previously discussed, the present invention can be used duringdialysis therapy conducted at home and in dialysis treatment centers.The dialysis treatment centers can provide dialysis therapy to a numberof patients. In this regard, the treatment centers include a number ofdialysis machines to accommodate patient demands. The therapy sessionsat dialysis treatment centers can be performed 24 hours a day, sevendays a week depending on the locale and the patient demand for use.

In an embodiment, the dialysis treatment centers are provided with thecapability to detect access disconnection during dialysis therapypursuant to an embodiment of the present invention. For example, one ormore of the dialysis machines within the center can be adapted for usewith an electrical contact coupling, induction coil coupling deviceand/or the like along with other components necessary to detect accessdisconnection as previously discussed.

In an embodiment, the coupling device can be directly attached to one ormore of the dialysis machines of the dialysis treatment center. Itshould be appreciated that the apparatuses, devices, methods and/orsystems pursuant to an embodiment of the present invention can beapplied for use during dialysis therapy administered to one or morepatients in the dialysis treatment center in any suitable way. In anembodiment, the treatment center can have one or more patient stationsat which dialysis therapy can be performed on one or more patients eachcoupled to a respective dialysis machine. Any suitable in-center therapycan be performed including, for example, hemodialysis, hemofiltration,hemodiafiltration, continuous renal replacement and combinationsthereof. As used herein, the term “patient station” or other like termsmean any suitably defined area of the dialysis treatment centerdedicated for use during dialysis therapy. The patient station caninclude any number and type of suitable equipment necessary toadminister dialysis therapy.

In an embodiment, the dialysis treatment center includes a number ofpatient stations each at which dialysis therapy can be administered toone or more patients; and one or more dialysis machines located at arespective patient station. One or more of the dialysis machines caninclude a chassis having one or more connectors for connecting a patientto the dialysis machine via a blood circuit allowing blood to flowbetween the patient and the dialysis machine during dialysis therapywherein a number of electrical contacts can be connected to the bloodcircuit in fluid communication with the blood allowing detection of achange in an electrical value in response to access disconnection as theblood flows through the blood circuit having an electrical signalpassing therein.

As previously discussed, the access disconnection detection capabilitiesof the present invention can be utilized to monitor and control a safeand effective dialysis therapy. Upon dislodgment of an access device,such as a needle or catheter, from the patient, the access disconnectiondetection capabilities of the present invention can be used to provide asignal indicative of dislodgment that can be further processed forcontrol and/or monitoring purposes. In an embodiment, the signal can befurther processed to automatically terminate dialysis therapy tominimize blood loss due to dislodgment as previously discussed. Further,the signal can be processed to activate an alarm which can alert thepatient and/or medical personnel to the dislodgment condition to ensurethat responsive measures are taken. It should be appreciated that thepresent invention can be modified in a variety of suitable ways tofacilitate the safe and effective administration of medical therapy,including dialysis therapy.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present invention andwithout diminishing its intended advantages. It is therefore intendedthat such changes and modifications be covered by the appended claims.

The invention is claimed as follows:
 1. An extracorporeal blood systemcomprising: an extracorporeal blood machine; an arterial line extendingfrom the extracorporeal blood machine; a venous line extending from theextracorporeal blood machine; and an access disconnection circuit fordetecting a disconnection of at least one of the arterial or venouslines from a patient, the access disconnection circuit including (i) asignal generation source having first and second signal generationsource electrical lines each in electrical communication with bloodtraveling through the same one of the arterial or venous lines, (ii) aconductive pathway electrically communicating blood traveling throughthe arterial line with blood traveling through the venous line, and(iii) a signal processing unit positioned and arranged to process asignal generated by the source to detect the disconnection of the atleast one of the arterial and venous lines.
 2. The extracorporeal bloodsystem of claim 1, wherein the arterial and venous lines include,respectively, arterial and venous needles.
 3. The extracorporeal bloodsystem of claim 1, wherein the signal processing unit is used to controlat least one of an arterial or venous blood pump or valve upon detectingthe disconnection.
 4. The extracorporeal blood system of claim 1,wherein the conductive pathway is not connected directly to the signalgeneration source.
 5. The extracorporeal blood system of claim 1,wherein the conductive pathway is not connected directly to the signalprocessing unit.
 6. The extracorporeal blood system of claim 1, whereinthe conductive pathway bypasses the extracorporeal blood machine.
 7. Theextracorporeal blood system if claim 1, wherein the signal processingunit is placed in electrical communication with blood flowing throughone of the arterial and venous lines.
 8. The extracorporeal blood systemof claim 7, wherein first and second electrical lines are placed inelectrical communication with the signal processing unit and bloodflowing through one of the arterial or venous lines.
 9. Theextracorporeal blood system of claim 7, wherein the signal processingunit is placed in electrical communication with blood flowing throughthe venous line.
 10. The extracorporeal blood system of claim 1, whereinthe signal generation source is placed in electrical communication withblood flowing through the arterial line.
 11. The extracorporeal bloodsystem of claim 1, wherein the signal generation source is an inductivesource.
 12. The extracorporeal blood system of claim 1, which includesat least one electrical contact placing the conductive pathway intoelectrical communication with blood flowing thought at least one of thearterial or venous lines.
 13. The extracorporeal blood system of claim1, wherein the extracorporeal blood machine is of a type selected fromthe group consisting of: a hemodialysis machine, a hemofiltrationmachine, a hemodiafiltration machine, a continuous renal replacementmachine, a slow continuous ultrafiltration machine, a continuous venovenous hemodialysis machine, a continuous veno venous hemofiltrationmachine and a continuous veno hemodiafiltration machine.
 14. Anextracorporeal blood system comprising: an extracorporeal blood machine;an arterial line extending from the extracorporeal blood machine; avenous line extending from the extracorporeal blood machine; an accessdisconnection circuit for detecting an access disconnection of at leastone of the arterial or venous lines from a patient, the accessdisconnection circuit including (i) a signal generation sourcepositioned and arranged to inject an electrical signal into the arterialor venous lines, (ii) a conductive pathway electrically communicatingblood traveling through the arterial line with blood traveling throughthe venous line, and (iii) a signal processing unit including first andsecond electrical lines placed in electrical communication with bloodflowing through the same one of the arterial and venous lines, thesignal processing unit processing the signal generated by the source fordetecting the disconnection of the at least one of the arterial orvenous lines.
 15. The extracorporeal blood system of claim 14, whereinthe signal generation source is positioned and arranged to inject thesignal into the blood flowing through one of the arterial or venouslines.
 16. The extracorporeal blood system of claim 14, wherein thesignal generation source includes first and second electrical linesplaced in fluid communication with one of the arterial or venous lines.17. The extracorporeal blood system of claim 14, wherein the signalgeneration source communicates electrically with one of the arterial orvenous lines, and wherein the signal processing unit communicateselectrically with blood flowing through the other of the arterial orvenous lines.
 18. An extracorporeal blood system comprising: anextracorporeal blood machine; an arterial line extending from theextracorporeal blood machine; a venous line extending from theextracorporeal blood machine; an access disconnection circuit fordetecting an access disconnection of at least one of the arterial orvenous lines from a patient, the access disconnection circuit including(i) a signal generation source positioned and arranged to inject anelectrical signal into the same one of the arterial or venous lines,(ii) a signal processing unit positioned and arranged to process thesignal generated by the source for detecting the disconnection of the atleast one of the arterial and venous lines, and (iii) a conductivepathway, separate from the signal generation source and the signalprocessing unit, placed in electrical communication with the arterialand venous lines so as to electrically bypass the extracorporeal bloodmachine.
 19. The extracorporeal blood system of claim 18, wherein theconductive pathway is placed in electrical communication with bloodflowing through the arterial and venous lines.
 20. The extracorporealblood system of claim 18, wherein at least one of the signal generatingsource and the signal processing unit is placed in electricalcommunication with blood flowing though one of the arterial or venouslines.
 21. The extracorporeal blood system of claim 18, wherein at leastone of the signal generating source and the signal processing unitincludes first and second electrical lines each placed in electricalcommunication with one of the arterial or venous lines.